1. Field of the Invention
The present invention generally relates to a system and method for communication, and more particularly to a system and method for transferring and replicating information between spatially distinct points using engineered quantum states.
2. Description of the Related Art
Efficient and reliable transfer of information is crucial to the preservation of knowledge and the advancement of progress. Contemporary computers, which play an invaluable role in this area, are capable of increasingly rapid information processing primarily through the downscaling of their constituent integrated circuitry. This well-defined evolutionary process has engendered phenomenal progress in information technology during the last few decades. However, the current trend of shrinking conventional semiconductor-based technology cannot continue indefinitely.
At the heart of present-day electronics are semiconductor devices which, although microscopic, nonetheless operate by controlling the flow of electrical currents along circuit paths defined by wires and other conducting areas. In one analogy, electrons are essentially shoved into one end of a conducting interconnection and emerge from another end like water in a garden hose. Conventional electronic devices are much larger than the wavelengths of the electrons comprising the currents steered through them, so quantum effects are generally ignored. However, because present scaling trends will soon demand device sizes that approach the electron wavelength limit, the full wave nature of electrons must be considered and will play an increasingly vital role in device operation and performance.
Therefore, given this view of the inherent limitations on conventional semiconductor-based electronics, new systems and methods for information transfer that rely on, rather than ignore, the quantum nature of electrons are critically needed.
It is an object of the present invention to provide a system and method for transferring information between spatially distinct points without requiring the usual wiring and current transfer of conventional electronics.
It is a further object of the present invention to provide structures fabricated on a sufficiently small length scale (on the order of the electron Fermi wavelength) to enable the engineering of confined quantum states as desired.
It is a further object of the present invention to modulate these quantum states, for example by perturbing the electronic potential at a particular location, thereby encoding information into the quantum states. If the modulation frequency is lower than the frequency corresponding to the damping time of the structures, the quantum states may be modulated adiabatically, thus enabling information transmission without power dissipation.
It is a further object of the present invention to couple the perturbation (or a localized quantum response thereto) with quantum states guided throughout the structure. The invention then selects and focuses the distributed quantum states for detection at a location spatially distinct from the modulation point. The detection of the modulating information is performed specifically through the wave nature of the quantum states, versus mere electrical current flow as with existing devices. The information transferred is not limited to a given format, i.e. it may be analog, digital, or any combination thereof.
It is a further object of the present invention to exploit the orthogonality of quantum wavefunctions to enable multiple channels of information to be transferred simultaneously through the same volume of space without crosstalk. Further, information may be transferred in either direction, that is, both to and from both the modulation point and the detection point, simultaneously, as there is no inherent directionality to a quantum state.
It is a further object of the present invention to provide structures enabling logic functions and memory operations to be performed on the transmitted information.
The structure is preferably a resonator designed to have two antinodes, which are spatial locations where the electron density distribution is relatively large. If a transmitter (which is anything that affects a modulation in a quantum state) is placed at a first antinode and a receiver (which is anything sensitive to a modulated aspect of a quantum state) is placed at a second antinode, information transfer between the transmitter and receiver is optimized because the modulation affected at the receiver by the transmitter is maximized. Conversely, a transmitter located at a node (spatial location where a quantum state""s density distribution is zero) will have minimal ability to modulate a quantum state and therefore minimal ability to transmit a signal to a receiver. Similarly, a receiver placed at a node of a quantum state will detect very little modulation of the quantum state and hence have minimal ability to receive a signal.
Alternately, structures may be designed with more than one transmitter and more than one receiver. Changes to the physical structure of the resonator may also modulate the quantum states available for information transmission. Furthermore, the quantum states used for communication need not even be occupied to be modulated.
In the preferred embodiment of the present invention, the structure for communicating information is an elliptically-shaped quantum corral assembled from cobalt atoms on a conductive copper substrate. The transmitter is preferably a cobalt atom positioned at the first focus of the ellipse. The receiver is preferably a scanning tunneling microscope (STM) tip positioned above the second focus of the ellipse. The geometric properties of the ellipse project the particular quantum mechanical signature (e.g. Kondo resonance) of the cobalt atom at the first focus onto the second, empty focus. In effect, a phantom image or xe2x80x9cmiragexe2x80x9d of the real cobalt atom appears at the receiver at the second focus and influences the receiver in a manner very similar to what would result from a cobalt atom actually existing at the receiver. In this case, the receiver detects a strong dip in tunneling conductance at the second focus, indicating the presence of the cobalt atom at the first focus. An electron reservoir is usually necessary to allow the invention to be operated more than once.
The invention is not limited to this structure or modulation method, however. Theoretically, a single atom could serve as the transferring structure because its electrons are confined to quantum states that could be modulated on one side of the atom and detected on the other side of the atom, or on the other side of the universe. In that case, quantum states are engineered by selecting a particular atom and the specific energy levels to be modulated.
The present invention thus provides a unique and nonobvious structure and method which overcome the limitations of conventional microelectronics, and embody a new paradigm for information transfer.